In Penang, don't miss the Snake Temple.I think 2 days is enough for Penang if you have a car and go all out to see only those famous places without wasting any time. It's more of experiencing the culture.
Tourist spot:Kek lok si temple, botanical garden, air itam damm, batu feringhi beach. Shopping: Gurney Plaza, Island Plaza, Prangin Mall . Food: too many good places to go! To name a few: Eden Seafood Village, The ship Batu Feringhi, hawkers food etc.